Glossary · Chemistry
Titratable acidity
Also written TA, total acidity. Each is a name for the same thing, which is why none of them has an entry of its own.
Definition
The total concentration of titratable acid in a juice or cider, measured by neutralising a sample with alkali to an end point and expressed as an equivalent of malic acid in grams per litre.
- Subject
- Chemistry
- Also written
- TA, total acidity
In more detail
TA answers "how much acid is there?" while pH answers "how strong is it in solution?", and the two can move independently. A juice with a high buffering capacity can carry substantial acid at an unremarkable pH; another can taste flat while sitting at a low pH. Blending and acid adjustment need both figures.
Conventions differ. British and North American practice usually reports as malic acid, French practice historically as sulphuric acid, and the numbers are not interchangeable without conversion — a difference that has caused a great deal of confusion in translated tables.
Where this is covered properly
The glossary defines; these pages explain. Each is described in its own words.
Production
Acid adjustment
Correcting the acidity of low-acid juice before fermentation, usually with malic acid, and the difference between the pH question and the titratable acidity question.
Chemistry
Malic acid
The acid of apples, which supplies almost all the sharpness a cider has and, through pH, decides how vulnerable that cider is to everything that could spoil it.
Related terms
Terms that belong to the same part of the subject, or that this one is routinely confused with.
Chemistry
pH
A logarithmic measure of hydrogen ion activity, and in cider the single most important number for microbial safety. Apple juice usually falls between pH 3.2 and 3.9.
Chemistry
Malic acid
The dominant acid of apples and pears, giving the sharp, clean acidity of fresh juice. Its name comes from *malum*, the Latin for apple.
Chemistry
Buffering capacity
The resistance of a juice or cider to a change in pH when acid or alkali is added, arising from its weak acids and their salts — chiefly malate and potassium.
Fruit
Sharp
In the Long Ashton classification, a cider apple high in acid and low in tannin. Sharps supply freshness and lower the pH of a blend into a range where spoilage organisms are less comfortable.
Sensory
Acidity
The perception of sourness, and the sensation of freshness and mouth-watering it brings. It correlates with both titratable acidity and pH, but neither predicts it exactly.
Where to go next
- Cider glossary — The whole vocabulary, by subject and A–Z.
- Comparisons — Terms that are only really clear when set against the thing they are not.
- Search — Finds terms by their aliases and by their spellings in other languages.
Sources
What this page rests on. Where a source is marked as registered rather than read, CiderHQ is recording that the body is authoritative on the subject without claiming to have worked through the document itself. See our evidence policy for what each state means.
The Science of Cidermaking and associated technical writing
Andrew Lea · reference work · passage verified 2026-08-24
Written by a food chemist who worked at Long Ashton on apple phenolics. Unusual among specialist cider writing in that it is primary-research-adjacent: the author is describing work he did, and cites the literature. This is why it is registered at tier 1 for chemistry while a general cider book is not.
Cornell Cider Research and Extension programme
Cornell University, School of Integrative Plant Science · university · passage verified 2026-08-24
Runs cultivar trials in New York State and publishes juice chemistry for European cider varieties grown in a North American climate — the single most useful counterweight to treating English figures as universal.
Long Ashton Research Station cider fruit analyses
National Fruit and Cider Institute / University of Bristol · research institute · registered as competent for this subject · covers 1903–2003
The foundational body of cider-fruit science in English. Long Ashton produced the acid-and-tannin classification that divides cider apples into sweet, sharp, bittersweet and bittersharp, and analysed hundreds of cultivars grown at its Somerset site. Its figures are historic measurements of specific fruit at a specific place, not universal constants — a distinction CiderHQ preserves in every measurement record that cites it.